Bug Description

#2143 allows to use any as key for c.Locals(key, v). The RequestID middleware should be consistent with that.
This allows to use a custom type for context keys, like for other keys. The RequestID is likely read back somewhere else along other context keys.

How to Reproduce

See https://docs.gofiber.io/api/middleware/requestid#config

Expected Behavior

https://docs.gofiber.io/api/middleware/requestid#config should have ContextKey interface{}

Fiber Version

v2.42.0

Code Snippet (optional)

No response

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• I have checked for existing issues that describe my problem prior to opening this one.
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